Our group has previously published the Diagnosis-Specific Graded Prognostic Assessment (GPA) showing the prognostic factors associated with survival in patients with brain metastases (BM). The purpose of this study is to investigate the relationship of breast cancer subtype to the time interval from primary diagnosis (PD) to development of BM (TPDBM), number of BM at initial BM presentation and survival. We analyzed our previously described multi-institutional retrospective database of 865 breast cancer patients treated for newly-diagnosed BM from 1993 to 2010. Several factors found to be associated with survival were incorporated into the Breast-GPA, including tumor subtype. The GPA database was further analyzed to determine if the subtype correlated with the TPDBM, number of BM, and survival from PD. After exclusions for incomplete data, 383 patients remained eligible for analysis. The subtypes were approximated as follows: Luminal B: triple positive; HER2: HER2 positive/ER/PR negative; Luminal A; ER/PR positive/HER2 negative; Basal: triple negative. Patients with Basal (90), HER2 (119), Luminal B (98) and Luminal A (76) tumor subtypes had a median TPDBM of 27.5, 35.8, 47.4 and 54.4 months (p < 0.01), median survival from PD of 39.6, 66.4, 90.3 and 72.7 months (p < 0.01) and median survival from BM of 7.3, 17.9, 22.9 and 10.0 months (p < 0.01), respectively. Tumor subtype is an important prognostic factor for survival in patients with breast cancer and BM. Although TPDBM is not an independent prognostic factor for survival (and thus not part of the Breast-GPA), the TPDBM does correlate with tumor subtype but does not correlate with the number of BM. Patients with Basal and HER2 tumor subtypes have short TPDBM. Prospective studies are needed to determine if screening brain MRIs are indicated in patients with Basal or HER2 subtypes.
Bibliographical noteFunding Information:
Acknowledgments Dr. Mehta has served as a consultant to Abbott, Bristol-Meyers-Squibb, Elekta, Genentech, Merck, Novartis, Novo-cure, Tomotherapy and Viewray; he serves on the Board of Directors of Pharmacyclics, He holds stock options in Pharmacyclics and Ac-curay. Dr. Lin has served as a consultant to Novartis (\$10 K) and GlaxoSmithKline (\$10 K). Grant Support This research was supported in part by Grant W81XWH-062-0033 from the U.S. Department of Defense Breast Cancer Research Program, to RJW, and by NIH Grant P30-CA77598 utilizing the services of the Biostatistics Core, Masonic Cancer Center, University of Minnesota shared resource.
- Brain metastases
- Breast cancer
- Graded prognostic assessment
- Radiation therapy
- Stereotactic radiosurgery